Annelid

Annelids Fossil range: Cambrian - Recent
Glycera sp.
Scientific classification
Kingdom: Animalia Superphylum: Lophotrochozoa Phylum: Annelida Lamarck, 1809
Classes and subclasses
Class Polychaeta (paraphyletic?) Class Clitellata*    Oligochaeta - earthworms, etc.    Acanthobdellida    Branchiobdellida    Hirudinea - leeches Class Myzostomida Class Archiannelida (polyphyletic) *Some people think that the subclasses under Clitellata are actually classes

Annelids are a phylum of Invertebrates. Sometimes they are called by their Latin name Annelida. They include the segmented worms, with about 15,0000 known species. Well known species are earthworms and leeches. Annelids can be found in most wet environments. Some of these species are parasitic or mutualistic. This means they live together with (or inside) another organism. A mutualistic relationship is beneficial to both organisms. Their size varies from under a millimetre to about 3 metres. The largest known species is the seep tube worm (Lamellibrachia lymnesi), which is related to the giant tube worm.

Annelids are made of one or more body segments. Each segment has one or more rings. These rings are called annuli (singular: annulus). Annelids reproduce sexually by hermaphroditic cross-fertilization. Annelid Worms have nerve tissue, a ganglia that makes up a primitive brain, a heart, and segmented body parts. They can regenerate cut off pieces of their body. Unlike sponges, which can come back together if ripped apart. They have a hydrostatic skeleton, a 1-way digestion system, and bilateral symmetry.

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Annelida

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Annelida